Random honeycomb structure

ABSTRACT

This disclosure involves a form of prefabricated structure such as commercial or industrial buildings, houses or enclosures employing an external skin bonded to an intermediate structural and insulating filler with an inner surface skin similarly bonded to the filler material. The external skins are preferably resin bonded glass fiber and the intermediate filler composes a random honeycomb structure made of cellulosic material, such as individual pieces of paper of random size each rigidified and bonded to adjacent pieces by a resinous binder which is compatible with the binder of the skins. The structure is shown in continuous panels and actually three dimensional structure configurations as well as discrete structural elements which may be used to replace comparable structural elements normally made of wood. Disclosed also are processes for continuous manufacture of structures employing the concept of this invention either in the factory or on site. The same basic structure is shown in various configurations. Illustrated are a number of panel sections employing the same structure arrangement but different filler density whereby the load bearing strength of the panel may be controlled and its insulating properties varied as well. Structural strength can also be varied by changing the dimensions and concentrations of resin/fiberglas of either or both external skin surfaces. Disclosed also are individual structural elements produced from waste paper material and resin bonded skins.

ilnited States Patent McCo [45] Ma 23 1972 RM HONEYCOMB STRUCTURE [57]ABSTRACT [72] Inventor; Wallace w McCoy, C/o John H Wagner Thisdisclosure involves atom of prefabricated structure such 1041 East GreenSt Suite 202, Pasadena as commercial or industrial bLllldll'lgS, housesor enclosures employing an external skin bonded to an intermediatestruc- Cal1f.9l10l tural and insulating filler with an inner surface skmsimilarly [22] plied: 1970 bonded to the filler material. The externalskins are preferably [21 APPL NOJ 15 364 resin bonded glass fiber andthe intermediate filler composes a random honeycomb structure made ofcellulosic material, such as individual pieces of paper of random sizeeach [52] US. Cl ..52/264, 52/309, 52/404 i idified and bonded toadjacent pieces by a resinous binder f which is compatible with thebinder of the skins. The structure Field of Search is shown incontinuous panels and actually three dimensional 52/264 structureconfigurations as well as discrete structural elements which may be usedto replace comparable structural elements References Clted normally madeof wood. Disclosed also are processes for continuous manufacture ofstructures employing the concept of UNITED STATES PATENTS this inventioneither in the factory or on site.

g i The same basic structure is shown in various configurations. l 7563O10/1939 52/404 Illustrated are a number of panel sections employing thesame 272527l 1 1/1955 C 52/309 structure arrangement but difierentfiller density whereby the 2849758 9/1958 1 load bearing strength ofthepanel may be controlled and its inum ey sulating properties varied aswell. Structural strength can also be varied by changing the dimensionsand concentrations of 52 fT gzd Mumgh resin/fiberglas of either or bothexternal skin surfaces. Disomey o n agner closed also are individualstructural elements produced from waste paper material and resin bondedskins.

4 Claims, 20 Drawing Figures 72p (Zr 72 m Ill 7 l d 72d 7 s /72 f 7 2 f72a 7 l 9 Patented May 23, 1972 6 .Sheetsx-Shout.

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FIG. '6

m w w w WALLACE W. MCCOY FIG. 8

Patented May 23, 1972 3,664,076

6 Sheets-Sheet I:

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INVENTOR.

WALLACE w. M -i:oY

Patented May 23, 1972 3,664,076

6 Sheets-Sheet 6 .v' 122 I23 v l FIG. 15 I l i I 1 v FIG. I6

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WALLACE w. Mc'ooy RANDOM HONEYCOMB STRUCTURE BACKGROUND OF THE INVENTIONGiven a careful analysis, the construction of houses has undergone onlyslight changes in the last one hundred years. The most prevalent form ofconstruction remains the balloon construction form of load bearing studwalls covered by exterior sheathing and an interior facing. This mode ofconstruction developed after the Chicago fire has become the standard ofthe industry. In the fields of industrial and commercial construction,significant advances have been made using such techniques as curtainwall, panel and precast lift wall approaches. Even these techniques donot fully utilize the advances which have been made in materialstechnology.

One example is in the area of resin bonded fiberglas, a materialcommonly used in automotive and marine fields but virtually unused inhousing structures. Another material advance which is just now reachingthe housing field is the use of ferro-concrete structures. This materialand form of construction, however, is incompatible with the need forthermal and sound insulation since it produces a thin (three-eighths tothree-fourths inch) highly conductive wall. In addition to the failureto use the new materials available, housing construction is fastdepleting our major natural resource, our forests. Despite restoration,the drain is continuous and with the current need to expand housing, therate will be accelerated.

The objects of this invention are all accomplished by the variousembodiments basically composed of a panel structure including two skinsurfaces, preferably of resin bonded fiberglas separated by anintermediate filler comprising random oriented resin rigidified particleof fragmented paper or other cellulostic material (interspaced) withintermediate random voids. The structure when viewed in section exhibitsthe general appearance of a random honeycomb. The intermediate fillermay be composed of cellulostic solid waste material that is currently abane of current urban existance and in this way is expected to reducethe drain on our forests.

BRIEF STATEMENT OF THE INVENTION I have determined that a major stepforward has been made in construction with the production in situ ofcontinuous panels employing and including outer skin, inner skininterconnecting insulation and structural core or fill to form acompleted structure of a shell in one continuous operation. Given thisbasic structure with a minimum of seams and a minimum of hand carryingand holding by individuals that cost the time of construction can begreatly reduced. I have also determined that interior and exteriorsurface treatment or finish can be selected or produced during theconstruction of the structure. I have further determined it is possibleto produce a single structural form which can be made to provide therequired load bearing strength and insulation capability and the two canbe varied relatively independently to produce any combination desired.

I have also found the structure is made up by a pair of skinlike surfacemembers which are hand preferably resin bonded as indicated above andare in spaced parallel relationship. Inbetween the two parallel skinsare a plurality of random oriented planar and non-planar pieces ofcellulostic material with a resinuous binder. The cellulosic pieces arepreferably produced by random tearing of sheets of the material toproduce edge fibers and in certain embodiments, the individual piecesare creased to provide a degree of inherent structural rigidity. Thepieces with their impregnating resin constitute relatively rigidinterconnecting members forming a random honeycomb-like filler. Thesepieces are bonded to adjacent surface skins by the same or compatiblebonding agent as used for the filler.

DESCRIPTION OF THE DRAWINGS The foregoing features of this invention maybe more clearly understood from the following detailed description andby reference to the drawings in which:

FIG. 1 is a perspective view of a structural panel in accordance withthe invention with a portion of the outer skins cut away to expose thecore material.

FIG. 2 is an enlarged perspective view of the comer of the core materialshown in FIG. 1.

FIG. 3 is a perspective view of a single particle of cellulose fiberbased material comprised of fragmented paper.

FIG. 4 is a perspective view of a single particle of fragmented paperafter deforming.

FIG. 5 is a cross sectional view of a comer of a complex panelstructure.

FIG. 6 is a perspective view of a structural beam having integrallybonded skin surfaces.

FIG. 7 is a perspective view of a pipe having inner and outer integrallybonded skin surfaces.

FIG. 8 is a perspective view of a structural panel having reinforcingribs molded as a part of the lower skin surface.

FIG. 9 is a block diagram of the manufacturing process for the preferredcore material.

FIG. 10 is a cross sectional view of an extruder applying integrallybonded skin surfaces to an uncured core preform to produce a compositepanel.

FIG. 10a is an alternate embodiment of a resin applicator forimpregnating the surface skins.

FIG. 10b is another alternate embodiment of a resin applicator forreinforcing and impregnating the surface skins.

FIG. 11 is a perspective view of an extruding machine producing ahollow, rectangular structural member.

FIG. 12 is a cross sectional view taken transversely across the machineillustrated in FIG. 11.

FIG. 13 is a perspective view of an extruding machine producing a hollowextrusion comprising the cross section of a gable-roofed buildingstructure.

FIG. 14 is a cross sectional view taken transversely across theextrusion illustrated in FIG. 13.

FIG. 15 is a perspective view of an extruding machine producing avertically oriented panel along a fixed form.

FIG. 16 is a simplified perspective view of an extruding machineproducing a hollow tube having a flat bottom surface.

FIG. 17 is a simplified side elevation view of an extruding machineproducing a continuous pipe in a trench.

FIG. 18 is an enlarged perspective view of the end of a machine as inFIG. 17, producing a partially entrenched pipe.

Now refer to FIG. 1 wherein a perspective view of a structural panel 10is shown having a core 11 with generally coplanar surfaces 12 and 13,and edges 14 exposed. The core structure illustrated is comprised mainlyof loose cellulosebase fibrous material which has been impregnated witha plastic binder and compressed into the generally flat panel formshown. Surfaces l2 and 13 are relatively smooth in texture, havingassumed the approximate surface conditions of the integrally bondedouter skins l5 and 16. Edges 14 are conversely somewhat rough andirregular, being illustrated as if the panel has been sawn from a largerpanel, and showing many edges and partial surfaces of particulatematerial and the interstices therebetween.

Now refer to FIG. 2 wherein an enlargement of the corner of the core 11in FIG. 1 is shown in sufficient magnification to more clearlyillustrate the structural make-up. A plurality of thin, irregularlyshaped and irregularly formed particles 20 are randomly oriented in aloosely compressed rigid form whereby their edges and surfaces providegenerally flat and relatively smooth surfaces 12 and 13. The randomorientation of the particles 20 cause the resin-impregnated particles tointersect in irregular edge-to-edge, surface-to-surface, andedge-to-surface junctions whereby the total volume included issubstantially voids between the particles, and the rigidity of thestructure is developed by the stiffness of many open and closed cellsformed by the resin-stiffened complex-formed particles spanning betweenresin-bonded intersections. The cells appear as a random jumble ofinterlocked polyhedral shapes, very much like a form of honeycomb corewith the cell walls in complex form and scrambled in every possibledirection.

The core of the fragmentary cross section illustrated in FIG. 2nominally has a grayish cast and a rough texture on the edge similar tocourse cork board. On closer examination, however, the rough texture isnot due to course, solid particles but to thin typically bent platelettsof material clearly identifiable as fragments of newsprint, rigidifiedby resin.

Great amounts of voids are a dominate feature. The voids range widely insize and shape, with the maximum size on the order of an inch long andvarying widths, up to are-fourth of an inch. Loose plateletts break whenso bent. Throughout the exposed surfaces, many cellulose fibers,interlocking, adhering to flat surfaces of paper or just free are veryobvious.

Experimental cores produced for tests, discussed later, when held in theair with one hand and struck soundly with the knuckles of the otherhand, give a damped ringing tone reminiscent of a wood plank, althoughif portion struck may also be accompanied by a small crushing sound, dueto the collapsing void in that immediate area.

The paper fragments visually range in size from roughly 2 inches down tothe limit of unaided vision. There appears to be a relatively evendistribution of size with an apparently large amount of free (at onetime) cellulose fibers.

The copius amount of voids are best seen in FIG. 2, along the edges. Itis difficult in these illustrations to depict the wide ranging sizespresent, not the cellulostic fibers that are everywhere. A preferredsize is one-half square inch.

Now refer to FIG. 3 wherein a typical particle of cellulose material 20is shown in a preferred embodiment employing waste newsprint paper asthe cellulose-base material. The particle 20 has a generally flatsurface 21, having small creases 24, bounded by very irregular edge 22generated by a tearing action, and is characterized by a ragged patternwith edge fibers 23 torn loose and extending from the torn edge.Experience has shown that more sharply cut particles do not have thecapability of retaining the impregnating resins at the particleintersections, whereas the torn edges promote better joint adhesion andimproved structural strength in the finished panel.

Now refer to FIG. 4 wherein a particle 20 is shown deformed considerablyout of its original planar form; and in which a plurality of creases orfolds 24 are provided in order to enhance the size and number of thevoids between the particles in the completed structural material, and toincrease the column strength of the individual particles. Severalmethods are employed to produce and increase the folds in the particles.Initially, the tearing is done in a fragmentation process which strikesand tears the paper with considerable speed and violence, creating thesmaller creases 24 shown in FIG. 3. Then the resin impregnation isaccomplished in a mixing operation having an impeller action withsufficient vigor to further deform the particles. Subsequently, thecompression of the mass of material both in injecting the material intoa press and in compressing the panel to the desired thickness anddensity increases the folding by crumpling the precreased particles.Structural strength can also be varied by changing the dimensions andconcentrations of resin/fiberglas of either or both external skinsurfaces.

Now refer again to FIG. 1 wherein skins 15 and 16 are shown definingplanar surfaces on each side of the panel 10. The composite structure isformed as the resin-impregnated skins l5 and and the mass ofresin-impregnated loose, crumpled particles are simultaneously shapedand cured into an integral unit. The skins l5 and 16 may be completelyomitted from the panel for some specific structural applications wherethe surface texture and durability of the molded core faces 12 and 13 isadequate. Various resin concentrations will alter the appearanceconsiderably, as will the texture of the mold surface used. Many of thepanels fabricated as experimental models have exhibited pleasing colorand textures, and have a surface appearance very similar to dark-coloredcork board paneling.

The skins are preferably made of resin-bonded glass fibers. The glassfibers may be in the form of fabric, woven roving,

chopped roving, random mat and prepregs of any of these. The glassfibers used generally in experiments to date have been of the fabricvariety, for ease of handling although chopped gun blown mat and randommat have been found to be satisfactory. Normal glass fiber length forthe blown random mat was 4% inches. The glas fabric used for the bulk ofthe experimental panels was low cost, gray goods, 7% oz. triple strandfabric.

The resin system used in the skins is commercially available polyestertype with the following composition:

Resin System,

Dilution Monomer,

Inhibitor,

Activator, dimethyl phthalate, 0.6 percent,

Catalyst, methyl ethyl ketone peroxide, 1% percent, all percentages areby weight compared to the basic resinmonomer weight.

In some applications, it is desirable to have a panel which has a verydurable and weather resistant surface on one side, and a softer finishon the other side, as might be characterized by an outside wall of ahome or office. A suitable panel may be made by leaving the texture ofthe core exposed inside, and providing an integral outside skin of avery durable and weather resistant material, such as, laminatedfiberglas.

There are similarly many applications were it is imperative to have verydurable finishes on both surfaces, such as homes inhabited by smallchildren, schools, and other high traffic buildings. In these cases,suitable skins such as laminated fiberglas, polyvinyl sheets, and evenwood or simulated wood may easily be included at the time of panelmanufacture, and become permanent, integrally bonded parts of the panelstructure.

The nature of the manufacturing process wherein both the skins and thecore are formed and cured as an integral unit makes a much wider rangeof skin materials not only usable, but very practical from the viewpointof cost, strength, and appearance. Since the skin material before curingmay be nothing more than a resin-wetted, limp membrane, and the surfaceshape, texture and finish is replicated from the mold surface, then theskin material selection is extremely broad. For example, fiberglascloth, which is usually coarse, loosely woven fabric, when saturatedwith resin and formed in a mirror-smooth mold will take on the moldfinish and become a glossy, impervious, and easily maintained wallsurface. Similarly, other textiles may be excellent choices fordecorative walls to produce very durable and attractive surfaces rangingfrom cotton prints through cheesecloth to colored burlap, where thefabric is visible, any texture is available from the mold surface, andthe final wall could resist even steamcleaning if necessary.

There are less complex skin materials, such as papers, that are suitablefor integral panel formation, whereas they would not be practical tobond to a previously made core, such as in the processes used forhoneycomb panel manufacture. Compression-bonding of a geometrichoneycomb sandwich panel invariably leaves the pattern of the hexagonalcells on the surface of the paper faces, just as the longitudinalcorrugations are visible on corrugated paper board. Since in thisinvention the core particles are randomly distributed and partiallycrushed before curing, the flat surfaces of the core beneath the skinsare relatively smooth, planar and provide added structural strength andbroad support areas for the skins. As a result, there is greatly reducedprint-through of the core texture, and there is never a regulargeometric pattern visible. As a result, the surface skins may beselected from thinner and lighter materials than is possible with ageometric patterned core.

The use of Kraft papers is very common in building materials, and iswell suited to use in the invention for applications having little or nomold texturing. In such decorative finishes as simulated brick or stone,the skin material must stretch to conform to the depth changes in themold, and therefore softer papers, including creped papers, papertowelling and soft industrial tissues, are more suitable.

The structural properties of the panels may be varied to best suit thestresses involved in the end use of the panels. The two basic areas ofdesign parameters to be varied are in the strength of the core materialsand in the strength of the integral skins. In applications requiringhuge puncture resistance, the need for heavy skins is obvious. Inapplications requiring resistance to heavy column loading, it isnecessary to provide higher strength and higher density in the corematerials. In applications requiring high bending strength, such as forunsupported spans, a stronger lower skin in tension is combined with afairly dense core to carry the compression loads.

Test panels were built up by hand using the following process. A moldwas made using an aluminum plate bottom surface which has a coating ofTeflon (tm) and sides of wood coated with the parting agent. A layer ofglass fabric, above described, is placed on the bottom plate andsaturated with the same or compatible catalyzed resin. The requiredamount of the prepared core material is placed in the mold. (Therequired amount is determined by the desired compression ratio and thefinal thickness of the finished panel.) A sheet of glass fabricsaturated with resin is placed over the top of the core material and thewhole mass is compressed to the final desired thickness by weighting atop plate, which is of the same composition as the bottom plate. Theentire assemblage is allowed to polymerize in the mold. On completion ofthe polymerization process, the assemblage is removed from the mold andadditional layers of catalyzed resin are applied to the skin surfaces bybrush or squegee, and allowed to polymerize. With the completion of thisstep, the test panels are finished.

A set of core samples were assembled to test the properties of the corematerial. The method of assembly was the same used for assembling thetest panels by hand described above, but without applying either skin tothe surfaces of the core. The appearance of the finished test cores weresimilar to the cores in the test panels.

Other material was used for potential core material. Dry straw, intendedfor feed use, was found very satisfactory. The length of the strawranged from 12 inches down to material that looked and behaved likepowder. There was also present 5 to percent dirt and other ill-definedrefuse material. This seemed to have little negative effect on thestrength of the material.

Still another material tried was fresh grass clippings and dropped elmleaves. The presence of the water from the fresh green grass acted likean inhibiter to the polymerization process. It was necessary to bakethis sample for 12 hours at 180 F. before the core sample wasacceptable. The grass and leaves were used au natural, withoutfragmenting or masticating them. There was very little impregnation ofthe leaves or grass by the resin. This produced a core that hadinacceptable strength. 1f the material were dried and fragmented beforeassembly, then the core produced would be acceptable.

The ratio of resin to paper is on a weight bases. The final density isin pounds per cubic foot. The equivalent solid density is found bytaking the estimated solid density of the resin at 107 pounds per cubicfoot and the density of used newsprint at 36 pounds per cubic foot,applying the resin to paper ratio as a factor to determine what thedensity of the entire assemblage would be if there were no air voids init. The ratio between this value and the actual finish density is takenas the ratio of solid to void space in the core.

The newspaper used for the core contained a wide variety of paper types,including slick surface magazines. All of these paper types were foundusable except paper that was treated with chemicals that prevented theabsorption of the resin into the fibers of paper. If the percentage ofthis type of paper was kept below 10 percent or if the paper was treatedto increase the absorbant properties, then this paper had littledelitorius effect.

Compression tests were made on the assembled panels. The panelswithstood compressive loads up to 160 pounds per square inch with nosigns of failure nor visible damage. The skins for this test panel were0.05 inches thick, containing one layer of 7% oz. gray goods glassfabric. The core used in the test panel had properties similar to coresample four that will be described below.

The physical properties of the core material were determined from theskinless core samples described earlier. Various ratios of resin topaper were used as were different ratios of the compression of the corematerial. The results of this test sequence are summarized:

Panels have been fabricated and tested for mechanical properties withoutany skins, with skins as minimal as lightweight cheesecloth, and withmuch heavier skins, including chopper fiberglas matting underlying wovenglass fabric. Core samples have also been fabricated and tested usingvarying densities of paper particles and resin concentrations. In someexperiments, natural materials were used in part or wholly as theparticles. These experiments were generally successful where a naturalorganic substitute closely approximated the configuration and absorptionof the paper particles. Where the natural substitute particles weregenerally flat or at least thin and crinkled, and where they could bemasticated to increase crumpling and provide a loose pattern of edgefibers, the ideal particles were simulated closely enough to providestructural soundness. A number of samples made in densities of from 6 to20 pounds per cubic foot, having total void volumes of from to 94percent, and mechanical properties well suited to sawing, drilling,nailing, and the like.

Now refer to FIG. 5 wherein a more complex shape for a structure isshown in a typical comer cross section 25. The core material 14, asshown in FIG. 1, extends between the two skins l5 and 16 to form a rigidstructure. The complete structure having the comer shape isresin-impregnated, compressed and cured in a suitable mold providing thefinish and shape of the structure. All of the same parameters that arevariable for a simple panel are also variable in the more complexstructural members, the only significant difference being the shape ofthe mold used to produce the structure.

Now refer to FIG. 6 wherein a structural element 28 is shown having acore 14 and side skins l5 and 16, as shown in FIG. 1, and additionallyhaving edge skins 29 and 30 to complete the longitudinal enclosure ofthe core 14 to form a completely encased structural shape. Each of thefour skin finishes is produced by a mold surface which providestexturing and shape during curing of the resin-impregnated compositewhereby the result is an integrally bonded structural member. A typicalexample of the end result is a 2 4 dimensional alike and directlyinterchangeable with wood structures of the same dimension.

Now refer to FIG. 7 wherein a pipe 31 is shown having a circular crosssection core 32, surrounded by an outer skin 33 and lined with an innerskin 34. The core material 32 is made up of the material described inFIG. 2, and both the inner and outer skin finishes are produced by moldsurfaces providing texturing and shape during curing of theresin-impregnated composite whereby the pipe is an integrally bondedstructural member.

Now refer to FIG. 8 wherein a ribbed panel 38 having a core 39 made upof the material described in FIG. 2, an upper skin 40, and arib-contoured lower skin 41. Both of the skin finishes are produced bymold surfaces providing texturing and shape during curing of theresin-impregnated composite whereby the ribbed panel is an integrallybonded structural member. In the configuration shown in FIG. 8, aunitary floor and support structure is produced. This continuous lowerskin 41 forms the tension member of the assembly and the entire flooracts as a unitary structural and surface assembly. The thickness of thefloor and skins, as well as filler-to-resin ratio, may be varied toproduce a floor of the required strength and dimensionalcharacteristics. The complete bonding of the numerous particles to eachother and to the skin and the total absence of natural sheer planar inthe structure enhance its structural integrity.

In each of the foregoing embodiments, the same structural combination isused. One characteristic of this invention is that the same combinationmay be used to produce a lightweight non-self-supporting filler to astructural member. The panels may be varied in thickness, density andsize at will and in the production of continuous walls or panels, thethickness and density may even be varied as the structure is produced byvarying the mandral separation and feed rate of material in the processdescribed below. In this manner, for example, the same structure may beused as interior non-load bearing and as exterior or load bearing wallswith only a change in the above parameters.

Now refer to FIG. 9 wherein a block diagram is shown for a preferredembodiment of the manufacturing process for the core material. Rawmaterial for the particles is shown as bulk paper 45, used newspapers46, and waste material 47. The selection of raw material depends on costand availability. Almost any cellulose fiber-based material is usable,and studies have shown even man-made trash to average 70 percentcellulose fiber content. However, optimization of the mechanicalproperties of the core will require control limits on raw materialdensity, absorbtivity and tearing characteristics. Optimum skinthicknesses are 0.05 to 0.1 inch.

The raw materials, preferably used newspapers 46 which are available inlarge volume at very lost cost, are fed into a fragmenter 50. Thefragmenter receives the paper into a chamber where high speed rotatingfingers strike and tear the paper into at least lightly creasedirregular fragments. The fragmented material is conveyed to a mixer 51where rapidly rotating blades impact the fragments to further creasethem and also mix in the resin 52 and catalyst 53. The resin istypically a polyester commercially available at low cost, including aresin system of unsaturated polyester with maleic and phthalicanhydrides and a styrene dilution monomer, using hydroquinone stabilizerand a cobalt napthenate promoter. The catalyst is typically methyl ethylketone peroxide.

The resin-impregnated particles are then conveyed to an extruder 54which partially compresses the mixture, thereby increasing the creasingof the particles somewhat, and extrudes the mixture into a continuousformer 55. The premiously cata lyzed resin-impregnated mass of particlesis further compressed into a desired shape by mechanical means by theformer 55 and is retained in the desired shape and becomes at leastpartially cured as the core material progresses through the former. Thepreferred embodiment of the manufacturing process for the core materialis shown as a continuous process wherein the output is a structuralmember 56 of undetermined length having limited width, thickness andshape established by the continuous former 55. An alternatemechanization is a batch process whereby measured amounts of materialsare processed in successive batches and the output is then a sequencedseries of individual pieces having all dimensions controlledsimultaneously.

The process for the manufacture of core material for integral curingwith one or more skins is substantially the same, except for onesignificant change in the operating mode of the former 55. When skinsare desired on the final structure, the former is adjusted to compressthe core to slightly less than the desired final thickness, and theoperating time and temperature are adjusted so the mixture does not curein the continuous former. The output of the process then is not a rigid,cured core structure 56, but instead is a slightly oversize uncuredpreform 57 suited for additional processing to complete the panelsstructure. Either output may be selected as an operating mode of thesame basic process and equipment.

Now refer to FIG. 10 wherein'a simplified extruder 58 is shown producinga panel having exterior skins. The output of the former 55 as in FIG. 9is shown producing an uncured resin-impregnated preform 57. The preformmoves at a uniform rate synchronous with moving webs of skin membranematerial 60 and 61 supplied from rolls 62 and 63, respectively. Webs 60and 61 are impregnated with resin by applicators 64 and 65, and theresin is activated with catalyst by applicators 66 and 67. The webs 60and 61 and core per form 57 move together at a flared entrance formed bythe contour of the extrusion die wall 71 and 72. Temperature control asrequired by the panel thickness and resin characteristics is establishedby heater means 73 to promote curing, and by cooler means 74 to assistin removing exothermic heat from curing. The final taper of entrance 70and the spacing between die walls establish the thickness and crosssectional contour of the finished panel.

The movement of the panel materials through the extruder is produced bythree cooperating forces. First, the continuous former 55 supplies thepreform under pressure which tends to make the core flow through theextruder. Second, rollers 75 and provided with external power and engagethe cured walls of the finished panel 76 to pull the panel out of theextruding die walls 71 and 72. Third, a tension means 77 is provided tostart the process in operation when the die may not yet be filledsufficiently for normal operation. Friction of the work against the diewalls is controlled by the use of non-stick surfaces, such as Teflon, aswell as commercial parting agents. The friction is minimized in mostapplications where the die walls must provide texturing for the outersurfaces of the skins. In order to replicate a complex three-dimensionalsurface, however minute in depth, the die surface must move along withthe skin surface. In an extrusion process, this necessarily implies acontinuous surface, much like a conveyor belt 80 shown partiallysupported by rollers 81.

How refer to FIG. 10a wherein a means for very uniform application ofcatalyzed resin is shown as an embodiment of the combination ofapplicators 65 and 66 or the combination applicators 64 and 67. The webof skin material 60 passes between a pair of pressure rollers 81 and81a. A resin reservoir 82 and a catalyst reservoir 83 supply resin andcatalyst to the surface of roll 81, which in turn transfers the mixtureto web 60 at the junction of the pressure rolls. Control of the flowrate of the resin mixture with respect to the velocity of the web willproduce a meniscus 84 in which a constant rolling and mixing of theresin mixture takes place, and permitting a uniform amount of themixture of be carried with the web between the pressure rolls.

Now refer to FIG. 10b wherein a means is shown for applying a skinmaterial substantially made of non-woven fiber material, such as choppedglass fibers. The web 60 may be a very flimsy membrane, such ascheesecloth of thin tissue paper. A mixture of resin and catalyst 85 issprayed from a mixing spray gun 86 incorporating cutting and impellingrolls 87 and 88 so driven as to draw fiberglas roving between the rollsand dispense cut fibers 91. The fibers 91 are spray coated with resinmixture 85 to become the resin-saturated matting 92 carried by themoving web 60.

Now refer again to FIG. 10 illustrating the cross section of an extruder58 in the process of manufacturing a panel. Additional skins may beplaced orthogonally to those shown in the illustration by simplyduplicating the components shown at to the section plane illustrated.This arrangement then extrudes structures having all four sides boundedby integrally made surface skins. By varying the relative widths of theorthogonally placed webs and die surfaces structures may be producedcontinuously ranging from thin, edge-sealed panels to large, rectangularor square beams for structural use as illustrated in FIG. 6. Beams soextruded may duplicate the sizes of dimensioned lumber, so that 2X4s, 2l2s, or even l2 l 8 s are available in unlimited length without grain,shrinkage, knots or warpage. The ability to vary density and skinstrength at will offers the opportunity to match the structuralproperties of the beam closely to the loads expected.

Now refer to FIG. 11 showing a perspective view of a machine 100 soarranged to extrude a completely closed hollow structure 101. Thecomplete extruding machine 100 is comprised substantially of fourorthogonally disposed extruders 58 as shown in FIG. 10. The extrudingmachine is carried on a means of self-propulsion 102, visible in part asa tracked vehicle. A continuous former 55, as described in the blockdiagram of FIG. 9 and shown in FIG. 10, supplies the core preform to thefour interconnected extruders 58, 58a, 58b and 580. The outer webs 61,61a, 61b and 610 may be seen coming from supply rolls 63, 63a, 63b and630; the inner rolls and webs being hidden from view. Ideally, the webs61, 6la-c are of greater width than their corresponding side of thefinished structure to allow for overlap of the comers and increasedstrength. The four extruded panels 76, 76a, 76b and 760 are shownemerging from the extruding machine as a rectangular tube 101 havingclosed, integrally made corners similar to the comer section describedand illustrated in FIG. 5. The panel drive rollers 75 are not shown inFIG. 11, and the extrusion force is instead aided by tension members 77,77a, 77b and 770 mutually fastened to an anchor means 103, whereby thefree end of the tube 101 remains in a stationary position as theself-propulsion means 102 carries the machine along the surface. Thestructure 101 may be of sufficient size to constitute an entire room orenclosure.

Now refer to FIG. 12 wherein the transverse cross section taken throughextruding machine 100 shows the rectangular tube 101 being formed insideand outside by the compression and shaping action of outer extrusion diesurfaces 71, 71a, 71b and 710, and inner extrusion die surfaces 72, 72a,72b and 72c.

Now refer to FIG. 13 showing a perspective view of a more complexextrusion machine 110 so arranged as to extrude a multi-panel closed,hollow structure 1 1 1 of gable roof building form and including panelsused as a floor 112, side walls 113 and 113a, a ceiling 1 14, a truss115 and roof sections 116 and 1160. All of the interconnecting panelsare integrally bonded and formed by machine 110, similar in function tomachine 100 shown in FIGS. 11 and 12, but more complex in shape, andcomprised of interconnected extruders of the type shown in FIG. 10,arranged and sized to produce the gabled extrusion shape 1 l 1 Now referto FIG. 14 wherein a transverse cross section taken across shape 11shows a number of outer die surfaces 71d through 71s cooperating with anumber of inner die surfaces 72d through 72s to compress and shape thegabled extru- Now refer to FIG. showing a perspective view of a singlepanel extrusion machine 120 so arranged as to extrude a vertical panel121. The extruder itself, similar to extruder 58 in FIG. 10, has onlyone die surface 122 associated with the selfpropelled machine, the otherdie wall 123 being a fixed form along which the machine 120 travels. Theself-propelling means 124 moves the extruding machine along a wallsimilar to a concrete form wall, extruding the panel along the wallwhich may be later removed to expose the other surface of the panel. Thefreedom of movement of the machine permits the spacing between die wall122 and the fixed form wall 123 to be varied in operation, therebyproviding a means of constructing wall panels of continuously varyingstrength, weight and insulation values.

Now refer to FIG. 16 wherein a very simplified representation of anextruding machine 130 is shown producing a pipe or tunnel structure 131including a circular internal surface and a generally flat exteriorbottom surface 132. This extruded form is well suited for above-groundtransmission of materials due to the design versatility that can beproduced by the basic extrusion system. The inner skin of the tube maybe made very high in hoop stress capability to carry fluids underpressure. The core material is an excellent insulator to reduce thepossibility of overheating or freezing the transmitted fluids, and theouter skin ofiers security from ultra-violet degradation as well asmalicious or accidental puncture of the inner, highly stressed tube.

Now refer to FIG. 17 wherein a simplified representation of a pipelaying extrusion machine is shown manufacturing a pipe 151 by extrudingthe pipe in unstressed straight form directly into a trench 153. Theadvantages of this form of manufacture is in the ease of transportationof dense bulk raw materials to the pipeline site, as opposed to the lessefficient transportation of bulky factory-made pipe lengths, and thetotal elimination of the need for welding or couplings dictated by thelength of a truck bed.

Now refer to FIG. 18 showing an enlarged view of the end of the extruderof the machine 150 as illustrated in FIG. 17, with the pipe only partlyentrenched. In the configuration shown in FIG. 18, the trench mayactually act as the lower-half mold for the insulating filler and onlyemploy an outer skin 152 on the upper half with a continuous inner liner153. This system results in some saving of material in non-pressureapplications where a minimum of cost is the predominant factor.

In all of the foregoing figures, the concept of this invention and itsvarious applications in modes of insitu production have beenillustrated. The primary characteristic of the invention relates to theuse of resin rigidifing discrete particles interlaced with large voidareas, while used alone or in combination with protective surface skinsbound to the rigidified particles. One specific resin system isdisclosed in the application. It is recognized that other systems inaccordance with wellknown practice in the plastics art might be used.Similarly, two compatible systems may be usedone for the filler andanother for the skin. The selection of the particular resin particleswill be dictated primarily on the basis of the application for the finalstructure and the economics, since the resin typically constitutes themajor cost of the structure.

Employing the in situ production of continuous structures, the laborcost of production has been minimized. These steps of handling,transportation, and erection of the structures have been virtuallyeliminated.

The above-described embodiments of this invention are merely descriptiveof its principles and are not to be considered limiting. The scope ofthis invention instead shall be determined from the scope of thefollowing claims including their equivalents.

What I claim is:

1. A structure comprising a three dimensional shape including continuousrelatively impervious facing defining inner walls and a ceiling,continuous relatively impervious facing defining outer walls forming theexterior weather surfaces of the structure and the roof thereof, saidinner and outer walls each comprising rigid resin bonded skins and anintermediate filler in resin bonded engagement with the inner and outerwalls whereby said inner and outer walls are in spaces rigidrelationship, said filler comprising discrete crumpled planar randomoriented particles of resin rigidified paper and defining a randomhoneycomb structure with a plurality of voids constituting 80 to 94percent of the filler by volume;

said filler constituting a structural load bearing structural corehaving compressive strength in the order of 45 to lbs. per square inch.

2. The combination in accordance with claim 1 wherein said inner andouter walls comprise resin bonded fiberglas.

3. The combination in accordance with claim 1 wherein said paperparticles are in partially crushed configuration.

4. The combination in accordance with claim 1 wherein said structureincludes integral loadbearing floor portions constituting continuationsof the inner and outer skins, whereby a unitary enclosed structure isdefined.

2. The combination in accordance with claim 1 wherein said inner andouter walls comprise resin bonded fiberglas.
 3. The combination inaccordanCe with claim 1 wherein said paper particles are in partiallycrushed configuration.
 4. The combination in accordance with claim 1wherein said structure includes integral loadbearing floor portionsconstituting continuations of the inner and outer skins, whereby aunitary enclosed structure is defined.